Effect of conjugated system extension on structural features and electron-density distribution in charge–transfer difluoroborates

A comparative structural study of two related donor–acceptor pyridine-based BF2 complexes, namely, 3-(dimethylamino)-1,1-difluoro-1H-pyrido[1,2-c][1,3,5,2]oxadiazaborinin-9-ium-1-uide, C8H10BF2N3O (1), and 3-{(1E,3E)-4-[4-(dimethylamino)phenyl]buta-1,3-dien-1-yl}-1,1-difluoro-1H-pyrido[1,2-c][1,3,5,2]oxadiazaborinin-9-ium-1-uide, C18H18BF2N3O (2), containing a dimethylamino group and either the shortest (in 1) or the longest (in 2) charge-transfer path known until now in this family of compounds, is presented. Single-crystal X-ray diffraction analysis supported by computational investigations shed more light on these systems, indicating, among other aspects, the predominance of C—H...F contacts in 1, the formation of antiparallel dimers held together by π–π interactions in both compounds, and the involvement of fused BF2-bearing rings in the charge-transfer process.

Analytical simulations of the Fokas system; extension (2 + 1)-dimensional nonlinear Schrödinger equation

This paper studies novel analytical solutions of the extended [Formula: see text]-dimensional nonlinear Schrödinger (NLS) equation which is also known with [Formula: see text]-dimensional complex Fokas ([Formula: see text]D–CF) system. Fokas derived this system in 1994 by using the inverse spectral method. This model is considered as an icon model for nonlinear pulse propagation in monomode optical fibers. Many novel computational solutions are constructed through two recent analytical schemes (Ansatz and Projective Riccati expansion (PRE) methods). These solutions are represented through sketches in 2D, 3D, and contour plots to demonstrate the dynamical behavior of pulse propagation in breather, rogue, periodic, lump, and solitary characteristics. The stability property of the obtained solutions is examined based on the Hamiltonian system’s properties. The obtained solutions are checked by putting them back into the original equation through Mathematica 12 software.

Fine-Tuning the Biological Profile of Multitarget Mitochondriotropic Antioxidants for Neurodegenerative Diseases

Neurotransmitter depletion and mitochondrial dysfunction are among the multiple pathological events that lead to neurodegeneration. Following our previous studies related with the development of multitarget mitochondriotropic antioxidants, this study aims to evaluate whether the π-system extension on the chemical scaffolds of AntiOXCIN2 and AntiOXCIN3 affects their bioactivity and safety profiles. After the synthesis of four triphenylphosphonium (TPP+) conjugates (compounds 2–5), we evaluated their antioxidant properties and their effect on neurotransmitter-metabolizing enzymes. All compounds were potent equine butyrylcholinesterase (eqBChE) and moderate electric eel acetylcholinesterase (eeAChE) inhibitors, with catechols 4 and 5 presenting lower IC50 values than AntiOXCIN2 and AntiOXCIN3, respectively. However, differences in the inhibition potency and selectivity of compounds 2–5 towards non-human and human cholinesterases (ChEs) were observed. Co-crystallization studies with compounds 2–5 in complex with human ChEs (hChEs) showed that these compounds exhibit different binging modes to hAChE and hBChE. Unlike AntiOXCINs, compounds 2–5 displayed moderate human monoamine oxidase (hMAO) inhibitory activity. Moreover, compounds 4 and 5 presented higher ORAC-FL indexes and lower oxidation potential values than the corresponding AntiOXCINs. Catechols 4 and 5 exhibited broader safety windows in differentiated neuroblastoma cells than benzodioxole derivatives 2 and 3. Compound 4 is highlighted as a safe mitochondria-targeted antioxidant with dual ChE/MAO inhibitory activity. Overall, this work is a contribution for the development of dual therapeutic agents addressing both mitochondrial oxidative stress and neurotransmitter depletion.

МЕТОД ВИЗНАЧЕННЯ ОСНОВНИХ ПАРАМЕТРІВ ВАНТАЖНОГО ЛЮКА В ХВОСТОВІЙ ЧАСТИНІ ФЮЗЕЛЯЖУ ЛІТАКІВ ТРАНСПОРТНОЇ КАТЕГОРІЇ

A method has been developed for determining principal parameters for aft cargo door of transport aircraft. A list of input data is given and a technique for finding them is described. An example based on an existing transport aircraft is considered. The following has been used as source data: basic cargo nomenclature to be transported by the designed aircraft, cargo overall dimensions and weight, methods of loading and mooring, loading facilities. More over the design, operational and regulatory parameters are needed, such as landing gear configuration, its bottoming system, extension of rails of the upper equipment for loading/unloading, cargo trajectories during loading and airdropping, codes of the international regulatory bodies such as FAR, CS, AP. Based on the source data, the principle of determining the dimensions of the cargo compartment, cargo floor and the loading sites in the form of a ramp with a pressure bridge, and air stairs is given. The relation between the ramp length and the cargo floor length is described taking into account the loading, unloading and air dropping operations. Correct calculation of these parameters is the most important task, because performance of the future transport aircraft directly depends on the solution. The technique of determining the cargo door opening, development of the load-bearing structure of the transport aircraft fuselage aft section, its main strong elements – the cargo door beam, the ramp, the attachment units, the ramp locks – is given. The interconnection of the ramp load-bearing structure with the load-bearing structure of the fuselage aft part, the options for transferring loads perceived by the ramp to the frame are described. Examples of two types – flat and volumetric – of the cargo door beams, as well as the method of their assignment are considered. Trajectories of the extreme points of the in-gauge load are determined using graphical method for loading, unloading, and airdropping operations. Taking into account the positions of these trajectories makes it possible to select the desired cutout in the fuselage aft section. While designing the aft cargo doors the main features are highlighted. These features when considered make it possible to determine the most optimal parameters of the cutout, the cargo door type and its components.

An exocyclic π-system extension of the phenanthriporphyrin framework: towards azaaceneporphyrinoids

An exocyclic π-extension of phenanthriporphyrin reduces the macrocyclic antiaromaticity of the formed expanded carbaporphyrinoids.